Urban Methane Emissions Rose 10% From 2020 to 2023 Despite City Climate Pledges

TL;DR: Urban methane emissions climbed about 10% from 2020 to 2023, according to satellite analysis published in PNAS. The rise occurred despite numerous city pledges to reduce the potent greenhouse gas.

Context Researchers from the University of Michigan used the TROPOMI instrument on the Sentinel‑5P satellite to track methane over 92 cities worldwide from 2019 to 2023. TROPOMI measures gas concentrations by detecting sunlight reflected off Earth’s surface, providing near‑daily, global coverage. The study focused on urban cores and their surrounding areas where landfills, wastewater plants, and leaky gas lines often sit. Methane traps heat far more effectively than carbon dioxide over short timescales, making its reduction a quick climate win.

Key Facts The analysis found that methane emissions from the 51 C40 cities grew roughly 10% between 2020 and 2023, while non‑C40 cities saw a 12% increase over the same period. Erica Whiting, a graduate student in climate and space science at the University of Michigan, said cities have begun trying to cut methane emissions and she hopes to monitor those efforts. Rob Jackson, an Earth system scientist at Stanford University and chair of the Global Carbon Project, noted that there is no evidence of decreasing methane emissions from cities in most world regions. He added that the pandemic‑related lockdowns of 2020 complicates interpretation, but the overall trend shows cities are not on track to meet pledge targets.

What It Means The results suggest that current urban mitigation strategies—such as upgraded waste management or leak detection—are not yet delivering measurable declines in methane at a global scale. Satellite‑based monitoring offers a tool to verify progress and pinpoint missing sources. Policymakers should watch whether upcoming waste‑to‑energy projects and stricter gas‑line standards begin to reverse the upward trend in the next reporting cycle.